Unidirectional valve



FIG. 1 is a front perspective view of a unidirectional valve, showingthe new design.

FIG. 2 is a top plan view thereof;

FIG. 3 is a right side elevational view thereof, the left sideelevational view being the mirror image of the right side elevationalview;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevational view thereof; and,

FIG. 6 is a rear elevational view thereof.

In the drawings, the broken lines depict environmental subject matteronly and form no part of the claimed design.

The ornamental design for a unidirectional valve, as shown anddescribed.